1. Field of the Invention
The present invention relates generally to an office chair in which the back rest is pivotable relative to the chair base and, more particularly, to a mechanism which selectively limits the angle of tilt of the back rest.
2. Description of the Related Art
Many chairs are available for use in office environments in which the back rest of the chair is pivotable relative to the chair base. These chairs have the advantage of allowing the user to periodically adjust his or her seating position and avoid fatigue which can accompany being seated in a single position for prolonged periods of time. An example of such a chair is disclosed in U.S. Pat. No. 4,792,187.
Often, chair controls which allow for tilting of either the seat or back rest of a chair can be somewhat complex and expensive devices. Typically, these devices use spring and linkage systems which serve to bias the chair back rest and limit its movement so that the back rest can tilt only through a preferred angle. Excessive tilt, for example, can cause the chair to be unstable as the user leans back in the chair.
Accordingly, it is desirable to provide a control for a chair which is capable of selectively limiting the angle of tilt of the chair back rest in a positive and reliable manner. It is further desirable to provide such a control which is simple and cost effective to manufacture. Still further, it is desirable to provide such a control which is easy to operate by the chair's user.